The discussion on diesel-electric gave everyone a chance to air their opinions on the subject.* Here's a new boat from Island Pilot, the Island Pilot DSe Hybrid: http://www.dsehybrid.com/

"The DSe Hybrid sets a new standard for cruising economy - on a sunny day, she can cruise indefinitely at speeds up to 6 knots WITHOUT BURNING A DROP OF DIESEL! You can live on the hook for months at a time with ZERO diesel. All your power needs can be met by the 6+ kW Solar array, modern battery and electric drive-train technology from Glacier Bay. She is the ultimate in Green Cruising."* (From the web site)

I doubt this is an ocean crosser, but for the 98% of us that will never cross an ocean anyway, who cares.* She may not be the prettiest boat ever made; you may not like cats.* But I think she points to a viable future for this technology.* Like any technology, diesel-electric can only become better and more efficient as time goes on.*

According to Sea Magazine this boat prices out at $500K, not that bad for a 60 footer.* I know I'm talking a different class of boat here but you sure can't get a 65 Nordavn, a 58 Krogen, or even a 58 Grand Banks for anywhere near that.

Well, you're not going to get a GB58 for any price since to date they've not made one They do have a 59' Aleutian, but the largest boat in the Grand Banks line is the GB52 (not counting the three 66-footers they made that didn't work).

The concept of electric power is great--- it's the generation of that power that's the problem. We (Boeing) just flew a small plane powered by fuel-cells, but this technology is not suited for large aircraft. It could be ideal for powering airport ground equipment that today is typically powered by diesel, like belt loaders, cargo loaders, ground-power carts, tugs, etc.

The concept of getting electricity from solar energy is even better because you don't have to make anything (other than the solar converter) to get the power. But I think solar converter technology has a long way to go before it really becomes practical from a design aspect. Covering the entire top of a boat as they did with the Island Pilot works, but from a design aspect is not so great. For example, how vulnerable are the panels to the marine environment? I know a lot of long-range sailboats have small arrays on them to keep their batteries charged up, but I don't know what the service life of the panels are like. If they can develop really efficient solar conversion technology to where the array or panel can be very small for the amount of power it produces, then it will become more practical for things like boats, vehicles, etc.

I wonder if the fuel-cell route isn't perhaps the best direction to go for a marine propulsion system.

Going green is like a fad. There is always a certian percentage that will leap on the band wagon of anything new and green is new. Hybred cars are so expensive only those that could afford to drive a 10 mpg car can afford them so the reason to own them now is prure social/political/fad motivated. Most of the green guys are making a statement. They are at the leading edge of technology, leading the inferior mass of humanity ( followers ) such that we will eventualy get smart ( like them ) and embrace the new ways. I'm going to leave this super green stuff to the do gooders, green freaks and hollier than thou guys to present themselves as saviors of the planet and those of us that aren't so smart. At some point in time, however, we will need to embrace much more efficent ways reguarding power use and production. We don't need solar panels and wind mills to do it either. Those of us collectively on this forum could quickly evolve into a place where we would be useing about one tenth of the fossil fuel we do now. Smaller boats to fill our needs, longer full displacement hulls, the most efficent engines ( possibly desiel electric ), larger propellers, better fairing of under water gear, less windage, ceasation of over powering and many other fuel saveing methods are at our disposal right now, most not even high tech. Any new boat can be made very fuel efficent with little or no high tech equipment. But most of us can't afford new boats. If we sold our old boats someone else would be poluting with them and if we were to run our old boats off the edge of the earth we'd be even less likely to be able to afford the new green boat. Going green now, however, affords a small degree of R@D to pave the way for the super green stuff when it becomes absolutely nessessary ... say when fuel gets to 10 or 15.00 per gallon ...and that time will come ..the big question is how long will it take.

My hat's off to Island Pilot for being an innovator in this area. My wife and I considered them but decided it was just too risky given that they were going directly from the scale model to Hull No. 1 -- no prototype. I can see that in a traditional boat but not in something this unique. They've also missed several self-imposed deadlines which is a cause for concern. It was originally slated to be introduced last year, then this year at the Miami show. Now I believe it's by private appointment only -- not sure when available. Anyway, I wish them luck. Conceptually it should work. I'm sure that we will see much more emphasis on fuel efficiency and alternative fuels in the coming years.

Any new boat can be made very fuel efficent with little or no high tech equipment. But most of us can't afford new boats.

It is simple and easy to do, but not cheap, and un-masculine.(Smaller is better)

Simply install an engine drive combo that is optomized for the boat.

The usual TT will have an old tractor or lorry engine marinization that is rated 80 , 120 to 180hp.

The owner will brag that he travels at 2gph and think thats great.

2gph is 30 to max! 38 hp so the boat would better with a smaller lighter more modern engine of max 50hp.

Simply using the swept volume at cruise , and matching that swept volume with a tiny, higher speed engine (and purchasing the new engine with a deeper reduction gear) will allow a 25 to 50% REDUCTION IN FUEL BURN.

Saving a buck or two an hour will take a long time to pay for the replacement, unless it was time for a rebuild anyway.

The problem I see with the "smaller engine in a trawler" theory is that there is no margin for error or emergency. There is no extra power available to power through the current when you need to, either for convenience or emergency.

Sometimes things happen that need the extra knot or two. You might save money/fuel for years on end and then need an extra knot to get out of the weather and you wouldn't have it.

Of course it's all a matter of skill and luck. Some might be able to boat their entire lifetimes without problem with the smaller engine, others maybe not.

Ken's point is certainly the case in the PNW where currents of up to 10 knots or more can be encountered. Of course you usually don't want to be messing around in currents that strong because they are usually associated with narrow passes and so have the attendant whirlpools, overfalls, etc.. But there are bodies of water like Johstone Strait, Rosario and Haro Straits, etc. where the current can knock two to four knots or more off your speed despite the water conditions being fine. We try to plan our trips to take advantage of the current but it's not always possible, or some legs will be with the current and others against. Having some extra power when it's needed has benefited most of the boaters I know.

They claim 6 knots on solar. That's a 6.5 kw array, which is about 8.5 hp power output (~750 watts/hp). So that implies that a 20 hp engine (or a pair of 10s, since it's a cat) should be adequate, and should be burning under a half GPH at the 6 knot speed. That ought to cut a few $$ out of the cost.

BTW - I don't know where the 60 footer reference came from - the web site shows a LOA of just under 40'.

I'd also be curious how many hours a day (especially in the sunny PNW) you could get 6.5 KW out of the array.

Sorry, Chris, you're right.* It does appear to be a 39' 6" boat.* I didn't notice that on their site.* I was quoting what I read in the latest issue of Sea Magazine.* It has an article on page 14, which has photos of the boat and says it is 60' X 25'.

I went back and looked at the Island Pilot site.* Half way down the home page you can click a link for their brochure.* In it they say they have a smaller mono-hull version coming out next year and the 60 footer is scheduled for 2010.*

Needing extra power is not nessessary. It's nice to have but if your'e serious about efficency you won't go there. Also ( if your'e serious ) you'll have a full displacement hull and won't have ( for all practical purposes ) any extra speed as the hull won't allow it. I tried to minimize power when I repowered my Willard with 37hp but know now 30 - 32hp would have been fine ( better ). Minimizing power is hard to do as the cost of error on the low side is very high indeed. As I've said before one can go as low as 2hp per ton with a good slipery FD hull.

Yep, there are certainly stability advantages to the monohull (ultimate stability), and loading issues with cats. Even then, I don't thing they have to be enormous to gain efficiency. They can exceed the traditional hull speed ratio developed for monohulls and still obtain the efficiency of displacement cruising.

I looked at quite a few cats for coastal cruising but I find the beam too much of a detriment -- too hard to find dockage in too many places.

Larry Graf, formerly of Glacier Bay, is coming out with an interesting new line of single-engine cruising cats. He's designing them so they can be disassembled and shipped in standard containers.

Going green is like a fad. There is always a certain percentage that will leap on the band wagon of anything new and green is new....

Considering that "green" besides being the color of grass in spring is the most abused political force and the biggest excuse for sacrificing personal freedoms for the "common good" I must admit I am tempted to agree with you.

However there is a good side to what is intended by "green", despite (dare I mention) Al G and associates.
I've considered to install solar panels on my roof, yet the bill is $20,000 for 1KW/h system that will knock $100 off my bill every quarter. At that rate it takes 50 years to get my money back. Not a good proposal.
Solar water system $6000 to have "almost" free hot water... considering hot water systems are on off-peek electricity that is much cheaper, it would take some 60 to 70 years to get my money back let alone make some savings.

So the above, when good business for the manufacturers, are not for me.

Yet sails and kites for boats seem to be rather green to me. So going green may just means rigging some auxiliary sail to your motorboat?

As for the solar locomotive on a catamaran, it looks nice on paper. I hate to think of the cost of it all compared to similar diesel powered.

Take away solar for a moment, is there an advantage to diesel electric for marine propulsion?

Yes. Diesel electric is mostly all good. We had a a good conversation about it a short time ago. You can have 4 or 5 screws with single engine or multiple engines with single screw. Maneruverability in all configurations is better and much better with multiple screws. One gets extremly high torque at extremly low speeds. Also low vibration and engine and propeller shaft location freedom too. Much improved fuel efficency at cruise speed comes from much better propeller loading. See page 2 of General Discussion ... Electric Boat Engines ( motors ). Welcome to the Forum.

Very well put. It is strange how very high aspect ratio hulls can bend the rules the rest of us are bound to. A kayak can be PADDLED past hull speed ( as we know it ). I think the biggest disadvantage of cats is the huge weight penalty they suffer keeping the two hulls apart and yet together. While making headway into big quartering seas the twisting forces on the structure that connects the two hulls must be tremendous. Cats make me structually nervous and most designs won't slide sideways down the face of a large wave. They do save wetted surface by not needing as much of a keel but loose it all by needing all that extra weight in the form of the interhull structure that pushes the hull deeper in the water increasing wetted surface. The most interesting development in cats is the sudden high popularity of small and fast ferry boats. The state of Alaska has a big one but it seems to be more trouble than it's worth .. troublesome.